I think it would be a good idea if the next recomendation specified how to handel a special case for the xsl:number attributes grouping-separator and grouping-size.
In my application I wanted to produce numbers that are integers with no separator character (so that thousands would not be separated by a comma for example). In order to do this I had to set grouping-separator=" " and grouping-size="10000" which will be sufficient for very lagre integers; much larger than the application will ever encounter. However I think it would be better if grouping-separator="" (a null string) were sepcifically allowed as a means of turning "commas" off. The xalan parser for example (www.xml.apache.org/) gives a lot of java exceptions and can't handle it. Also, if grouping-size="0" were specified to mean that "commas" or whatever were turned off that would be another good way to do it (I would allow both methods).
Since the values for grouping-separator and grouping-size could be a data driven parameter into a template or stylesheet it would be a good idea to make it a bit more robust for this kind of situation.
I hope this idea was helpful and please let me know what you think of it. I look forward to hearing from you.
- Mike